monotribe drum trigger out

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crippletoe
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monotribe drum trigger out

Post by crippletoe » Wed May 23, 2012 2:28 am

Hi all,
can anyone explain how to get the individual drum triggers out of the monotribe?
I have seen images in the forum showing where are all the points on the board one should take these triggers from but when i tried to send these signals out to a jack socket i simply got contsant voltage signal rather then pulsing triggers.
is there somthing missing between the monotribe board and the socket?
(attached is an image that darenager posted in a thread a while ago. thanks for that.. :) )

Image

excuse a newb.
and thanks!

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darenager
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Post by darenager » Wed May 23, 2012 1:30 pm

I just used a cmos buffer connected to each of the 3 points shown, then the output of each buffer to the tip of your socket, ground to sleeve.

Really cool using the roll function with the trig outs :sb:

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crippletoe
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Post by crippletoe » Thu May 24, 2012 6:06 am

Ok Great!
I will try that.
can you explain in a simple way what it does exactly (the buffer) or is it too complicated?
I am just curious... thats all.
when connecting that trigger to my system i could see that voltage was constantly being sent out and not pulsing so i wonder what kind of signal is there.

anyhow, thanks!

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crippletoe
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Post by crippletoe » Thu May 24, 2012 7:48 am

also,
do you connect the CMOS buffer to voltage or is it passive?

matia
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Post by matia » Tue May 29, 2012 7:58 pm

i could, too, use just a bit of clarification regarding the cmos chip as i would love to integrate this mod into my monotribe.

any help is much appreciated!

-matia

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crippletoe
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Post by crippletoe » Wed May 30, 2012 2:11 am

Hi,
the original post says a "4050" was used as the CMOS buffer.
thats all i know.

matia
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Post by matia » Wed May 30, 2012 6:11 am

thanks for the reply. did you manage to make the mod work in the end? also, and this may seem totally silly of me asking so please forgive me, but, did you ground the jacks as well?

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crippletoe
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Post by crippletoe » Wed May 30, 2012 6:29 am

hi,
I didnt do the mod yet. and your question is not stupid at all...
i am very new to this as well and somehow keep running into all these questions that many people with some experience in electronics simply take for granted. its a very common problem we've been discussing for a while :) but i guess, thats the only way to learn.
i plan to order the CMOS chip, hoping its the right one, then i need to figure out whether i should power it, and if i yes, then how?
grounding the jacks is a legit question. from darenager's reply above, i would assume you have to.
wouldnt you?

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Post by matia » Wed May 30, 2012 6:38 am

yea you have to ground the jacks from what i've read too. i was thinking maybe something was funny with the grounding. let me know how things progress ... i got a paia drum tone kit coming so i though i would mod the ole monotribe for some programmable triggers ... the 808 and cr8000 are used up and there's just no more room on the cr ... plus i dread opening that thing up ... i hand wired all new switches for EVERY BUTTON ... it works now though :-)

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crippletoe
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Post by crippletoe » Wed May 30, 2012 6:44 am

well, if i manage to get this done, i will post it here.
there are too many question signs at the moment though...

lets hope.

perhaps one of the lovely forum visitors could throw us a tip.

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Post by crippletoe » Wed May 30, 2012 9:33 am

to whoever is viewing this post,
considering that my question from before was stupid and that one must supply 5v power to the buffer cmos, does anyonen know where on the monotribe one can access that power? is there a spot one can connect to?

this is, by far, one of the easies (potentially) and most useful mods for the monotribe and yet, it is the least documented... i wonder why...

thanks!

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roglok
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Post by roglok » Wed May 30, 2012 9:50 am

i don't have a monotribe, but if you take a look at the schematics korg released, you will see which components connect to the 5v line. just tap it from one of the 22k resistors connected to the npn transistors or follow the trace to find a suitable spot...

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crippletoe
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Post by crippletoe » Wed May 30, 2012 10:00 am

thanks, roglok.
will try that.
hopefully it will be easy for me to recognise a 22k resistor or an npn transistor.

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roglok
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Post by roglok » Wed May 30, 2012 10:07 am

as an alternative, you could use a general purpose NPN transistor wired as an emitter follower for each output. connect the trigger signal to the base, the collector to 5V, add a 1K resistor to the emitter and grab the buffered output from there...

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crippletoe
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Post by crippletoe » Wed May 30, 2012 10:17 am

cool stuff :D

let me refer you to one of my older posts on this thread above:
crippletoe wrote:i am very new to this as well and somehow keep running into all these questions that many people with some experience in electronics simply take for granted. its a very common problem we've been discussing for a while :) but i guess, thats the only way to learn.
in other words, it will take me about 2 weeks or more to decifer your last post :D :doh:
but hell! i really want to get to know how to do these things.
will simply and slowly climp up the learning curve....

thanks, i am sure that many people will find this tip useful as well!

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roglok
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Post by roglok » Wed May 30, 2012 10:58 am

haha, sorry... i hear you. i'm no engineer and probably not much further up the ladder than you...

i'd make a drawing for you, but i'm on a mobile device until next week... but i guess meanwhile it won't hurt if you tried to wrap your head around it and read some articles about how a transistor works. some basic knowledge helps a lot when tinkering with electronics :)

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crippletoe
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Post by crippletoe » Wed May 30, 2012 12:48 pm

thanks for being so understanding! :)
thats very nice.

I will do the reading in the meanwhile!

cheers!

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Altitude909
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Post by Altitude909 » Wed May 30, 2012 7:09 pm

you want more than just a buffer, you want a level shifter. The triggers are only 3.3v, you want to buffer those AND bring them up to 5V

This is what I use: http://www.ti.com/lit/ds/symlink/cd74hc540.pdf

Image

OE1 and 2 are shorted to ground, rest should be self explanatory

The 5V traces on the MT are the thicker ones (twice as thick as the others), just probe with a meter to verify
Last edited by Altitude909 on Wed May 30, 2012 7:57 pm, edited 1 time in total.

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DGTom
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Post by DGTom » Wed May 30, 2012 7:35 pm

The 4050 isn't a unity gain buffer like an op-amp.

As long as the triggers cross ~50% of VDD the output will kick out VDD, so 3.3V input will = 5V output.

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roglok
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Post by roglok » Thu May 31, 2012 12:03 am

oh, my bad... i assumed the internal triggers were already hot enough... depending on the external gear used it might work with a simple buffer stage anyway...

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crippletoe
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Post by crippletoe » Thu May 31, 2012 7:50 am

ok!
so just to confirm, because i am getting a little confused...
is the 4050 good enough here or not?
I believe darenager mentioned he used a 4050 and that it worked...

yes!

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crippletoe
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Post by crippletoe » Thu May 31, 2012 7:54 am

also,
anyone knows a good link that explains how to tap to a 5v trace on a circuit board?? <blush>

:hihi:

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Post by Altitude909 » Thu May 31, 2012 9:23 am

there is more than one way to do this, I use the 541 on mine its 8 channels which is over kill (u only need 3) but its easier to wire up, 4050 will be fine as well.. Just take a meter and start probing the big traces to find 5V

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roglok
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Post by roglok » Thu May 31, 2012 9:24 am

http://www.korg-datastorage.jp/Manual/monotribe_sch.pdf

as i said earlier, look at the schematics and find the components that connect to +5V (they are numbered both on the board and in the schematics)

they should share a common trace. this is your 5V supply line...

matia
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Post by matia » Thu May 31, 2012 1:26 pm

the problem with triggering becomes painfully apparent when using old Roland gear. I noticed it first with ALL DOEPFER products since their gate/trigger out on pretty much all the sequencers is + 5 volts which is just not enough to drive something like the old SH range excluding the 101. I believe the 606, 808, 909 ... all were +10 volts on the trigger out ... maybe more (12)

hence why it would be great to know a way to step up the monotribe's trigger voltage out beyond +5 volts if that's possible :-)

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